Signaling device for collapsing pneumatic tires



Dec. 3, 1924.- 1,520,665

E. ARNSDORF SIGNALING DEVICE FOR COLLAPSING PNEUMATIC TIRES Filed Nov.15, 1922 1 mlll/ Witnesses: Jnventor:

Ernst Arnsdm).

Fzftarmr ill ill

Patented Dec. 23, 1924.

UNITED STATES ERNST AR-NSDORF, OF NEUDAMM, GERMANY.

SIGNALING DEVICE FOR OOIILAPSING PNEUMATIC TIRES.

Application filed November 13, 1922.

To all whom it may concern:

Be it known that I, ERNST i-innsoonr. a citizen of the German Republic,and a resident of Neudamm, Neumark, Germany, have invented certain newand useful Tinprovements in Signaling Devices for Collapsing PneumaticTires, of which the following is a specification.

My invention relates to an improved signaling device for indicating theescape of air from and the consequent collapse of pneumatic tires ofmotor cars. For the safety of the occupants of a motor car and in orderto avoid serious injury to the pneumatic tires of such cars it is ofgreat importance that an early indication of the col lapse or deflationof the tires should be given. If a tire has become too flat the car isliable to skid and the driver has it no longer well in hand. Experiencehas shown that a puncture in the tire caused by the penetration of aforeign body into the airtube grows so quickly, that already after a fewrevolutions of the wheel the damage so serious, that it is practicallyimpossible to repair the tire again. In view of the high price of tiresthis is, of course, a serious loss. Proposals have previously been madeto give the driver of the car a signal, if the tire is becoming flat. Inmost proposals a rod or stem secured upon the wheel is sub jected to theaction of the air-tube, which in the highly inflated state forces therod back against the resistance of a spring. If the air escapes from theair-tube the spring will force the rod against the collapsing air-tubeand move the rod radially towards the circumference of the wheel andthereby gives a signal or grounds the ignition circuit, so that themotor of the car is stopped automatically. In the known devices thecatch which closes the switch is disposed upon the rod or stem. Therebythe reliability of the signaling device is rendered questionable,particularly if the catch has been accidentally bent, for instanceduring the removal. or exchange of a wheel or if the wheel has alteredits original position upon the shaft. Such defects can not be examinedwithout trouble and it is necessary that this and the many otherexaminations should be made at a glance, as neglect would render thewhole safety device useless. The constantly laterally projecting catchdoes not lend itself to a wide range of adjustment and consequently thesignal might be given Serial No. 600,728.

prematurely, particularly if the springs of the car give too much andthe clearance between catch and switch is not wide enough.

invention otters the greatest possible .7 .cty against such accidents bythe insci-lion of a further safety element into the devices foroperating the signal. According to my invention the rod or stem, whichmoves towards the circumference of the wheel when the air-tubecollapses, does not carry the etch but the catch is an arm hinged nearthe hub of the wheel and is locked in position by the rod, which onlyreleases it when the tire begins to become deflated, whereupon the catchflies outwardly and sets the signal. in operation. The catch reposes inits inoperative position within the periphery of the wheel and does notproject. so that it cannot he accidentally bent or otherwise damagedwithout this becoming visible at once.

Two embodiments of my invention are shown in the accompanying drawing inwhich- Fig. 1 a cross-section of the improved tie-vice applied to apneumatic tire with the rim and the part of the wheel necessary for theunderstanding of the invention.

Fig. 2 is a modified construction of the improved device.

Fig. 3 is a cross-section through theswitch.

Fig. a is a front-elevation of the same, F1 5 is a. cross-sectionthrough the switch along the line 5-6 of Fig. 3 and Fig. (l is a similarcross-section with the parts in a different position.

Similar parts are indicated by the same letters of reference throughoutall the figures of the drawing.

Referring to Fig. 1 it will be seen that between the beads of the outercover b of the tire wedge-shaped pieces or insertions a are inserted inthe usual manner, which are forced against the rim (Z by the inflatedairtube F). Upon one of these wedges a a stem is attached, which isguided in a tube d fixed upon the rim (Z and passes with a reducedportion h through a screw-cap e closing the tube d. A helical springwithin the tube (Z acts upon the shoulder of the stem 0 and tends toforce the stem 0 into the cover 6 The spring 7 is of such a strength,that its resistance is overcome by the fully inflated air-tube Z), butassumes the upperhand as soon as the pressure in the airtuhe drops andmoves the stem 0 towards the circumference of the wheel.

The stem 0 locks a catch a in its inoperative position which catch isfulcrumed at- 9% upon one or two spokes Z of the wheel. and is actedupon by a spring 0, which tends to turn it into the operative position,indicated in broken lines in the drawing and in which it is no longersituated in the diametrical plane through the wheel, but atapproximately right angles to it. The length of the catch a may beaccurately adjusted by means of a pin n screwed into it, so that whenthe pressure falls in the air-tube the stem 0 follows the collapsingtube and releases the catch n. The catch in its released position duringthe rotation of the wheel, contacts with an arm 2 of a switch 9 fixedupon the frame 1" of the car. The switch closes a circuit which gives asignal at the dashboard 11, of the car, which may be either visible,such as a lighted incandescent lamp o or audible, such as a ringing bellto (Fig. 2

In the place of the rod or stem 0, the tubular casing of the valve forthe air-tube b as shown in Fig. 2 may be employed. Referring to thisfigure it will be seen that valve casing 0 connected in the usual manner with the air-tube b is radially guided in the inner wooden rim dAround the casing 0 is wound a spring j, which tends to force the casingaway from the rim d The screw cap 0 of the casing 0 carries alockingtooth 12 which when the air-tube I), is inflated to its fullextent maintains the catch a pivoted on the spokes of the wheel in itslocked position.

As soon as the air-pressu re in the tire drops slightly it isoutbalanced by the pressure of the spring and the valve casing 0 movestowards the tire 5 The locking tooth 7L then releases the catch a, whichswings out sideways and closes the switch q.

The switch 9 comprises a casing g fixed upon the frame 1' of the car.Within the casing is disposed a shaft k, which carries a cam the end ofthe shaft is projecting from the casing is provided with a squareportion 7a upon which an arm 29 is fixed. ()ne wall a of the casing ismade of insulating materials and carries a contact spring 25 within thepath of the cam in. The contact spring t is provided with a terminalscrew i on which a cable 2' is attached which leads to the ignitionapparatus a or the lamp or hell contact near the seat of the driver. Thecam has solid contact across the casing with the frame "1' of the carand is also connccted with the motor and the ignition apparatus wherebythe latter may be grounded.

It will be understood that the details of the mechanism may be modifiedin various ways without departing from the spirit of my invention.

Having thus particularly described the nature of my invention, what Iclaim as new and desire to secure by Letters Patent of the United Statesis:

In a signaling device for collapsing pneun1atic tires. comprising acasing adapted to be secured upon the :trame of a vehicle, a switchwithin said casing, a swinging arm depending from said casing foractuating said switch, a spring returned swinging catch pivoted upon thespokes of the wheel, a member forced radially inward by the air pressureof the tire, and means upon the end of said swinging catch cooperatingwith means upon the end of said member for looking said swinging catchin inoperative position. whereby upon the reduction of pressure in thetire said member will release said swinging catch to enable the same toengage said swinging arm to close said switch.

In testimony whereof I aflix my signature in presence of two witnesses.

ERNST ARNSDORF.

Vitnesses E. HoL'rznnMANN, R. T. ANsrAoH.

